We opened ours right away and sent the thank yous right away. I think it is better that way because people know that you have received it. If you feel it is bad luck to use it before the wedding, just keep everything in the box until after the wedding. Some people do that because if something were to happen, you are required to return the gifts.

Definitely open them and send a thank-you note! We are not using any gifts we receive before the wedding, but etiquette dictates that you send a thank-you note before the wedding for any shower gifts and wedding gifts received before the wedding.